Bug Description

Horizon seems to be interpreting "-1" (unlimited) quotas literally when tallying quotas, setting the 'available' field to 0 instead of infinity (probably because the expectation used to be that an unlimited quota would always be returned as None).

The problem becomes more obvious in the context of ux improvements based on quotas such as https://bugs.launchpad.net/horizon/+bug/1033829, but it's also possible to check it by doing "nova quota-update --ram -1 <project_id>" then visit the project overview page: it will read "Used X MB of -1 MB Available RAM". It should be "Used X MB of inf MB Available RAM" -- although it would also be nice to display a nicer message when there are no limit!